1. Field of the Invention
The present general inventive concept relates to a computer and a power supply method thereof, and more particularly, to a computer and a power supply method thereof which can lower a range of an input electric power level supplied to a system unit thereof.
2. Description of the Related Art
A portable computer, such as a notebook computer and a personal digital assistant (PDA), having a battery attached thereto is widely utilized in that it can be carried and used as a mobile device. Generally, the computer uses an outer power source through an AC/DC adapter or conventional power devices, and also uses a battery as a secondary power source which can be recharged by an adapter.
FIG. 1A is a block diagram illustrating a conventional computer. As illustrated in FIG. 1A, the conventional computer is supplied with electric power of 19 V from an adaptor 1, and electric power of 6 to 8.4 V from a battery 2. Accordingly, a system unit 3 of the conventional computer receives an input electric power having a range of 6 to 19 V from the adapter 1 and the battery 2. As such a configuration has a large range of the input electric power, components, such as a metal oxide semiconductor field effect transistor (MOSFET) and an inductor, are required to have a large capacity when they are designed to output the same voltage, thus decreasing an overall efficiency and a battery life span.
To solve such a problem, narrow voltage direct current (NVDC) has been introduced. According to the NVDC, the electric power from the adapter 1 or the battery 2 is transformed into the level required to drive electronic components included in the system unit 3, thus decreasing the range of voltage level of the input electric power (VDC) inputted to a DC/DC converter 4.
However, as illustrated in FIG. 1B, a conventional NVDC causes a decrease in efficiency because the electric power received from the adapter 1 is not directly applied to the system unit 3 but applied via a battery charging unit 5. Also, the conventional NVDC requires a boost converter to step up the electric power received from the adapter 1 to the electric voltage level required for charging the battery 2.